OCTOBER 2001

A comfortable workplace (Part II)

Take a break! Yes, really - your productivity will improve!

All Ergonomists agree that it's a good idea to take frequent, brief rest breaks. Practice the following:

. Incorporating a short hourly break is a simple way to improve comfort at the computer. It is also a good time to do some simple stretching to reduce muscle tension and improve overall body circulation

. Eye breaks - looking at a computer screen for a while causes some changes in how the eyes work, causes you to blink less often, and exposes more of the eye surface to the air. Every 15 minutes you should briefly look away from the screen for a minute or two to a more distant scene, preferably something more that 20 feet away. This lets the muscles inside the eye relax. Also, blink your eyes rapidly for a few seconds. This refreshes the tear film and clears dust from the eye surface.

. Micro-breaks - most typing is done in bursts rather than continuously. Between these bursts of activity you should rest your hands in a relaxed, flat, straight posture. During a micro-break (< 2minutes) you can briefly stretch, stand up, move around, or do a different work task, e.g., make a phone call). A micro-break isn't necessarily a break from work, but it's a break from the use of a particular set of muscles that's doing most of the work (e.g., the finger flexors if you're doing a lot of typing).

. Rest breaks - every 30 to 60 minutes you should take a brief rest break. During this break stand up, move around and do something else. Go and get a drink of water, soda, tea, coffee, or whatever. This allows you to rest and exercise different muscles and you'll feel less tired.

. Exercise breaks - there are many stretching and gentle exercises that you can do to help relieve muscle fatigue. You should do these every 1-2 hours.

What about ergonomic gizmos? These days just about everything is labelled as being "ergonomically designed" and much of the time this isn't true and these so-called ergonomic products can make things worse.

"ergonomic" keyboards - most of these are keyboards where the alphanumeric keys are split at an angle. There is no consistent research evidence that most of the split-keyboard designs currently available really produce any substantial postural benefits. For most people a regular keyboard design works just fine.

"ergonomic" mouses (yes it's "mouses" not "mice") - many of these mouse designs or alternative input device designs can work well to improve your hand/wrist posture. However, it's important to check that you can use them with your upper arm relaxed and as close to your body as possible. Overreaching to an "ergonomic mouse" defeats any benefits of this design.

Wrist rests - these were very popular a few years ago, but research studies haven't demonstrated any substantial benefits for wrist rests. In fact, a wrist rest can actually increase pressure inside the carpal tunnel by compressing the undersurface of the wrist (take a look at you're the underside of your wrist and you'll probably see blood vessels that shouldn't be compressed!). Studies show that pressure applied to the underside of the carpal tunnel is transferred into the tunnel itself via the transverse carpal ligament and that intracarpal pressure doubles with a wrist rest compared with floating the hands over a keyboard. If you choose to use a wrist rest, use one with a broad, flat, firm surface design, and rest the heel of your palm on this NOT your wrist. Try not to rest while you're actually typing, but rest in between bursts of typing movements. Avoid soft and squishy wrist rests because these will contour to your wrist, restrict the freedom of movement of your hands, and encourage more lateral deviation during typing. Look at the surface of a typical wrist rest that's been used and you'll see that it gets eroded away, which means that the user has been sliding their wrists over the surface, which also compresses the blood vessels often visible at the wrist. Remember, your hands should be able to glide above the surface of a wrist rest during typing, don't lock them in place on the rest while you type.